hi,I don �t usually post when it is a grammar question but this sentence doesn �t look wrong. let me explain:
I am a very messy person (that �s the bit about my personal life...)
and it is a common joke with my friends and one of them often comes round my house and would for instance say or rather exclaim:
I �d never seen your floor swept!
I may sometimes say, to insist on something unusual: did you see my hedge trimmed? (now, I have to say that when saying that there is a pause in the sentence between the last two words-probably to make up for the fact that the words was/has been... were omitted)
I know that if natives say it it doesn �t mean it is correct...but still.
So to cut a long explaination short: I think the sentence is correct but there should be a pause when saying it between the last two words to make imaginary room for "since it has been"(I know guys! "imaginary room" isn �t a very accurate term when it comes to grammar but what the hell)
have a lovely evening
Jamiejules
P.S: before anyone starts, there is nothing wrong with a trimmed hedge!
(I hope I didn�t offend anyone... I am in a cheeky mood tonight)